I have a 94 YJ 2.5L 5spd with 131k on the OD. I bought it with 68k on the OD and the previous owner had apparently used non-synthetic oil. As soon as I took possession, I began using synthetics. Jeep has run well for the last 6 years with only some valve clatter at start-up and a little roughness once warmed.
I usually do my own oil changes, but recently, I decided that it might be time to go to a shop that offers a Bilstein Engine Flush service. After all, the Jeep had about 5 years in the hands of another owner and I really couldn't guarantee the regularity of the oil changes and the condition of the lubrication system etc. as a result.
Naturally, I had heard all the talk about the Bilstein Engine Flush being nothing more than a cash cow for auto repair shop operators; Click and Clack (the auto advice guys) basically stated the same, without any reservation. However, I use Bilstein shocks and had long been impressed with their function; and, I was a little skeptical that a German company, like Bilstein (which provides parts for Mercedes and other makes), would bring to market some kind of big, service-shop- Turbonator.
So I had the Flush done, had a Mobil 1 301 Filter installed (1.5 time stock oil filter capacity) and refilled with almost 5 quarts of full-synthetic. The Jeep runs like it's just had 100,000 miles trimmed off the OD. Any roughness is gone, clatter gone at start-up, quieter idle, revs super smoothly and basically feels like a brand new engine. It's only been a few days, but I am impressed with the apparent results of the Bilstein Engine Flush. Total cost for the Flush and Synthetic Oil change came to $127 at Sultze's Automotive, highly recommended auto repair and custom-machine shop in Norwalk, Ca (a 20 mile drive south of LA). I talked to the owner and he said he has been providing the Bilstein Flush service for the last 8 years.
Is the Bilstein Engine Flush a repair shop Wallet Vacuum or Scam? Yes and No. Shops that offer the service are suggesting that one should pay for the Flush service every 15,000 miles. Frankly, sold to consumers in that manner, the Bilstein Engine Flush is a rip-off. A Vehicle isn't going to see a major benefit having a Flush done every 15,000 miles versus the cost involved. But, you'll probably find the Flush service more than worth the money in the following circumstances:
1. On some newly-purchased used vehicles, generally the higher mileage examples.
2. On vehicles that you expect to keep for a while; Flush perhaps every three-five years or 50-100k miles just to keep the engine running like it has low miles.
3. On vehicles run in exceptional conditions, say 4x4s regularly off-road in dusty conditions, farm vehicles, vehicles use for work such as construction, hard-driving such as taxis/messenger/delivery/police.
4. Prior to changing a vehicle from petroleum oil over to synthetic oil.
:D